In some networking scenarios, there are needs for computers located in different domains or disparate networks and having different platforms and networking capabilities to talk to one another. For instance, the testing of computer networking and application interactions often involve getting one computer with certain testing configuration to interact with another computer with a similar or different testing configuration. For instance, in a test of distributed client-server interactions, one computer that supports only Internet Protocol Version 4 may try to communicate with another computer that supports only Internet Protocol Version 6 over a complicated network topology that might include firewalls, multiple domains, etc. One major issue for such communications is that the two computers may not even be able to form a connection with each other through regular network links. In other words, the two machines may not have direct network connectivity. For instance, the computers may be located on two different networks that have not established trust and thus does not allow messages to be routable across the networks. Also, the two computers may support different transport protocols and thus cannot directly send or receive messages from each other.
Moreover, even if the two machines can form an initial connection, there are other issues that have to be addressed before they can effectively communicate with each other. For instance, if secured communication is required, two machines on disparate networks have to be able to negotiate a security protocol to be used through a third machine that has connectivity to both without trusting the third machine. Also, in some cases one or both computers involved in the network communications may be down or otherwise unable to send or receive messages, and the reliability of the delivery of communication messages will be a concern. For instance, if the two computers communicate to each other as part of a testing operation, and one testing step of one computer is to install an operating system and reboot after the installation, it may not receive messages from the other computer during that period.